Process of forgery detection.



H. M. PILKINGTON.

PROCESS OF FORGERY DETECTION.

APPLICATION FILED MAR 5. 193.

1,135,919, Patented Apr.13,1915.

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MYEHTOR VWM [If Flt HERBERT MORRIS PILKINGTON, 0F ARVERNE, NEW YORK,ASSIGNOR; BY MESNE .ASSIGNMENTS, T0 LITHDTEX COBFOR-ATION, OF NEW YORK,N. Y., A CORPORA- TION 6F NEV] YORK.

PEOCESS OF FORGERY DETECTION.

which forged or spurious prints, engravings or the like, may be easilyand quickly detected, even when such forgeries are made in the 'mostskillful manner.

Further objects, :t'eatures and advantages will more clearly appear fromthe detailed description given below taken in connection with theaccompanying drawings which form a part of this specification.

In the drawings, Figure 1 represents a standard or original with whichthe forgery is to be compared; Fig. 2 represents a small transparencycorresponding to the original or standard; Fig. 8 represents atransparency produced on a small scale of the supposed for er and F1 4re )resents the lnia e pro ected by tne transparency of the supposedforgery.

In the making of prints, engravings and the like photographically, it isconvenient to first make an original, and then to make a photographictransparency of the original upon a relativel small scale, and then fromthis relatively small photographic trans parency or plate (usuallyglass) to'make the ultimate plates from which the issue of prints,engravings or the like, are printed. or made. I

In carrying out the improved paocess in the preferred form, there ismadefi'oin the small photographic plate -or transparency, and by thesame lens with which ,it was made, and with which the plates forn akingthe genuine prints, etc, were madefa standfard transjiarency on arelatively large scale.

Thisstandard transparency is made upon material which will not stretchyor warp, such as glass, and kept ready lornse for Specification ofLetters Patent. v

Pa-tented Apr. 13, 1915.

Applicationfile March 5, 1918. Serial No. 752,233.

the purpose of. detecting forgery at any time, according to the improvedprocess.

Whenever a supposed forgery is found, a photographic plate ortransparency of the same is made preferably by the same lens with whichthe standard.transparency was made, the transparency of the supposedforgery being preferably relatively small, and then an image isprojected from this transparency with the same lens onto the largepern'ianent standard transparency, and of such size as to registertherewith, preferably said small transparency being a com pleinent ofthe standard or larger transparenc vthat is, one being a positive andthe other a negative. If the supposed forgery is, in fact, a genuineprint or the like, the black portions of the projected image of thesmaller transparency will fall upon the correspoiiding transparentportions of the standard, and likewise, the light rays projected throughthe transparentportions of the small plate or transparency will-fallupon and register with the corresponding opaque portions of thestandard, the image fitting into the standard like a matrix, so tospeak, so that no light rays will pass through the stamlard. On theother hand, if the supposed forgery be in fact a forgery, then when theslight differences, which neces sarily occur therein, are thus magnifiedand the lines of one projected upon the other, there will be certaintransparent lines or spaces on the standard transparency which will notbe covered by the corresponding dark spaces or lines of the imageprojected from the small transparency of the supposed forgery, andconsequently the two will not register, and certain light rays will beseen to pass through the standard, thus at once showing that thesupposed forgery is, in

standa rd transparency and the transparency of the supposed forgery are,accordingl'to sible discrepancies between the standard transparency. andthe print to be tested, due to lens variations.

In the preferred manner oi practising the process the same lens is usedthroughout for producing a small transparency (from which the trueprints or engravings areproduced),-the large or standard transparency, v

the. small transparency of the ori 'nal forgery and for projecting theimage rom the same onto the stands rd. But if the standand is not madewith the same lens with which the smaller plate or transparency was madefrom which the genuine prints were produced, then'it is only importantfrom the standpoint of lens imperfection, to use the same lens in makingthe standard, the small transparency of the alleged forge1, and forprojecting one onto the other. his 1 s an important feature, for, asabove explained, any two lenses are seldom, if ever, alike, and by using"the same lens throughout, any imperfection will equally afi'cct v allparts of the process, and thus agreement would be found when making thefinal comparison if no forgery exists.

Fl 1. represents the standard trans arency which it will, be seencontains b ack.

distinctive lines A, although a fewv lines are an eater convenience, andthese, for the cotnc'reason, are wider than would be actualllyemployedin proportion to the size oi-the figure-shown, but it will be understoodthttthore mayibe many of these, so that it becomes practicallyimpossible for ahy one, by handto precisely imi ate thetsame from asmall scale of the print such as is tobe issued.

Fig. 2 re nesents the transparency orr'a reduced sea e correspondin tothe standard 1 transparency and which ms been formed from the original..This transparency is preferably made to exactly correspond with theoriginal-according to the prints or engravings which are to be made-thatis, so that the lineson the original being black are black on thetransparency.

Fig. 3 represents the transparency produced on a small scale from aprint which it is desired to compare with the original or standard toascertain whether it is a genuine print or forgery. This transparency ispreferably made to he the complement of the print from which it istakenthat is to say, what would be black or colored lines on the printare made to appear White, that is, as clear spaces on the transparency.

4 shows the image projected from the transparency of Fig. 3, and it willbe seen that the lines B therein are white or clear spaces. If the printfrom which the transparency of,Fig. 3 was taken is a true print, thenthe black spaces of Fig. 4. will genuine prints is available, it onlybeing im exactly coincide with'the white spaces of Fig. 1, and the whiteor clear spaces of Fig. 4 will fall exactly upon the black lines of Fig.1, provided the image is brought to precisely the same scale as Fig. 1,and is ad usted at such focus as to register therewith.

While it is preferred to make the so-called standard transparency at thetime that the genuine prints are made so that it may be filed away andpreserved, yet the standard may be made photographically directly fromone of the-genuine prints, engravings or the like, at the time that theforgery is to be detected, provided one of the original or portant tosecure the most accurate and re liable results, that the same lens beused in making this standard as is used in making the transparency ofthe supposed forgery, and in proitxztin the image of the same onto thestandard. urthermore, it is not necessary. to the broadest aspects ofthe invention that the comparison of the two bemadc by superposition byprojection in the manner stated, as they may be compared bysuperposition in any other suitable way which will bring'out thedifierences between the two.

Although the improvements have been described in rest detail withrespect to the referred orm of the invention, nevertheess it is notdwired to limit the invention tb such details, except as clearly pointedout in the appended claims, since various modi fications and changes maywell he made in the process without departing from the spirit and scopethereof in its broader as ects.

other copy and of the same size thercas.

2. The improved process of detecting forged prints, engravings and thelike, which consists in making a copy of the original photographicallythrough a lens, making a copy ofthc supposed forgery or the likephotographically through thosumc lens, and then comparing by projectingby means of the some lens, theimage of one copy upon the other copy andof the same size thereas.

3. The improved. process of detecting forged prints, engravings. and thelike, which consists in making a copy oflthe original photographicallythrough a lens, madng a copy of the supposed forgery or the'likephotographically through the some original photographically through alens upon a plate which will not warp orstretch, making a copy of thesupposed forgery or the like photographically through the same lens upona plate which will not warp or stretch, one of said copies beingtransparant and one smaller than the other, and then comparing the twoby projecting by means of the same lens, the image of one copy onto theother and of the same size thereas.

5. The improved process of detecting forged prints, engravings and thelike, which consists in making a copy of the original photographicallythrough a lens, upon a glass plate, making a copy of the supposedforgery or the like phctographhcally through the same lens upon a glassplate, one of said copies being smaller than. the other and one apositive and the other a. negative, and then comparing the two byprojecting by means of the same lens, the image of one copy onto theother and of the same size thereas.

6. The improved process of detecting forged or spurious prints,engravings and the like, which consists in making a transparencyphotographically on a relatively small scale from which the originalprints, engravings or the like are made, making a transparencyphotographically on material which will not stretch or warp and on arelatively large scale from the small transparency, making atransparency photographically of the supposed forgery with the same lensas was used in making the standard, and then projecting with said lastlens an image from the transparency of the supposed forgery onto therelatively large standard transparency at such focus as to registertherewith.

7 The improved process of detecting forged or spurious prints,engravings and the like, which consists in making a transparencyphotographically on glass on a small scale from which the originalprints, engravings or the like are made, making a transparencyphotographically and with the same lens as a standard on material whichwill not stretch or Warp, and on a relatively large scale from the smalltransparency, making a transparency of the supposed forgeryphotographically with the same lens on glass on a relatively smallscale, said lastmentioned transparency being a complement of thestandard,that is, one being positive and the other negative, and thenprojecting with the same lens an image from the transparency of thesupposed forgery onto the relatively large standard transparency at suchfocus as to register therewith.

In testimony whereof, I have signed my name to this specification, inthe presence of two subscribing witnesses.

HERBERT MORRIS PILKINGTON.

VTitnesses:

SAMUEL M. WARD, Jr., EDWIN Snonu.

